Transparent Nanocomposites of Non-Organophilic Clay/Amorphous Polymer

Abstract

Clay nanocomposites of amorphous polymers with ester groups were prepared by twin screw extrusion and injection molding. Although, in general, an organophilic clay is required to form good nanocomposites, we succeeded in preparing nanocomposites with good clay dispersion by using natural clay without organophilic agents. In this study, PETG, an amorphous polymer with excellent clarity, was used as the matrix polymer. The resultant nanocomposites retained high transparency and clarity despite the 5% clay content. Flammability properties were measured using a cone-calorimeter. The heat release rate decreased 54% for the PETG/clay nanocomposites compared to the neat PETG resin and the phenomenon of molten droplets (dripping) does not appear during the combustion. Therefore, high flame retardancy has been achieved. Furthermore, the tensile modulus of the nanocomposites increased by 50% over the neat PETG modulus. The evaluation of WAXD patterns and TEM observations indicated that the silicate layers of the clay were not intercalated nor individually exfoliated. Partial exfoliation and a decrease in the number of layers were, however, indicated.